This is preemption bug happens before 2.8.0, which also described in
Queue hierarchy described as below:
Assume cluster resource is 100 and all queues have same weights.
- queue-1-1 and queue-2 has apps. Each get 50 usage and 50 fairshare.
- When queue-1-2 is active, supposedly it will preempt 25 from queue-1-1, but this doesn't happen because preemption happens top-down, queue-2 could be the preemption candidate as long as queue-2 is less needy than queue-1, and queue-2 doesn't exceed the fair share which means preemption won't happen.
We need to filter out queue-2 since it isn't a valid candidate.